Conversion combustion chamber



April 16, 1940. M. 1.. MUELLER CONVERSION COMBUSTION CHAMBER Filed Aug. 23, 1937 i E LVVENTOR Marl Z 2 A. Mueller? mwwm Patented Apr. 16,1940

' UNITED STATES CONVERSION COMBUSTION CHAMBER,

Moritz L. Mueller, Grosse Pointe, Mioh., assignor to Borg-Warner Corporation, a corporation of Illinois Application August 23,

Claims.

This invention relates to a combustion chamber for use with a hydrocarbon burner for installation in heating equipment not particularly adapted to use such a burner. The combustion 5 chamber of the present invention is adapted more particularly for use in connection with a hydrocarbon burner employing a gaseous fuel, and is illustrated as it is used in connection with a burner which has means for supplying quantities of air under pressure to the combustion chamber after such air is mixed, in proper proportions, with a gaseous fuel.

As a general rule, the installation of gaseous fuel burners in old furnaces or boilers, originally designed for the combustion of coal or some other solid fuel, has proved too expensive due to the inemciency of a gas burner in such circumstances. The heating surface of such furnaces or boilers has not been designed with a View to the combustion of fluid fuels and the consequent ineiiiciency of these conversion installations has led to a mistaken belief that heating with such fuel is relatively expensive, causing home owners to regard such fuels as a luxury.

By employing the combustion chamber of the present invention in combination with such a fluid fuel burner it is possible to utilize any type of heatlngplant which may be in use in a home W without any major alterations.

It is an object of the invention to provide a combustion chamber which may be supplied in connection with a fluid hydrocarbon burner for emciently utilizing .the heat produced by such burner and causing the greater part of the heat to be transferred through the heat conducting surfaces of a furnace or boiler of any type.

A further object of the invention is to facilitate the installation of a combustion cham- W ber in old furnaces or boilers.

A still further object of the invention is to provide means, in connection with a fluid fuel combustion chamber, for forcing heat into and through the walls of a furnace or boiler for heat- M ing the surrounding air or water.

An additional object is to provide means for confining a fuel within a superheated chamber until it has thoroughly and efiiciently been burned, at which time it is forcibly expelled against a heat transfer surface.

Still further objects will appear more fully as the description proceeds.

In order to accomplish the foregoing objects, a there has been provided a combustion chamber 1937, Serial No. 160,435

built up of refractory material forming an enclosed space supported in a telescoping metal tray within which the heat of combustion is reflected back into the fresh fuel being fed into the chamber and which results in more com- 5 plete combustion of all the particles of fuel within the chamber. The chamber is provided toward the end removed from the fuel supplying means with an aperture through which the hot gaseous products of combustion may escape. l Such aperture is, however, partially blocked by means of a pressure battle which has a slot extending thereabout for causing the products of combustion to be deflected laterally and rearwardly with respect to the combustion chamber 35 and into contact with the heat transfer surfaces of the boiler or furnace.

In the drawings, in which similar reference characters are employed to designate similar parts, and which are illustrative of the preferred embodiment of the invention:

Fig. 1 is a perspective view of a fluid fuel burner and the combustion chamber which forms the subject matter of the present application,

certain parts being broken away more clearly to 25 I illustrate the construction of the combustion chamber;

Fig. 2 is a perspective view of the combustion chamber tray showing the forward blocks of refractory material in place; 39

Fig. 3 is a longitudinal vertical sectional view through the combustion chamber, showing the pressure baffle in place;

Fig. 4 is a transverse vertical sectional view through the combustion chamber taken approxi- 35 mately on the plane indicated by the line 4-4 of Fig. 3;

Fig. 5 is a horizontal sectional view through a circular boiler or furnace looking in the direction of the ash pit, taken substantially upon the 41' plane indicated by the line 5-5 in Fig. 6;

Fig. 6 is a vertical sectional view taken substantially upon the plane indicated by the line 6-6 of Fig. 5 and looking in the direction of the arrows;

Fig. 7 is a horizontal sectional view through a rectangular furnace or boiler taken upon a plane as indicated by the line l! of Fig. 8 and looking in the direction of the arrows;

Fig. 8 is a vertical sectional view of the boiler and combustion chamber shown in Fig. 7 taken approximately upon the plane indicated by the line 8-8 of Fig. 7 and looking in the direction of the arrows; and.

Fig. 9 is a perspective view of a baiile plate showing the underside.

In converting standard coal burning types of fm'naces to the use of fluid hydrocarbon fuels, it has previously been the experience of home owners that an installation of this type will be relatively ineflicient. Oil burners which employ a draft tube and a blower have been installed in such .a manner that the flame from the burner is simply blown into the fire pot of the furnace and reliance has been placed upon the heat radiated from the flame for transferring such heat through the heating surfaces contained in the walls of the furnace. Gas burners which have been previously installed were of the type which rely upon the pressure of the gas to inspirate the air needed for combustion and have accordingly produced a very low temperature flame upon which no reliance could be placed for the distribution of the heat from the flame by radiation alone as is the case in oil burners. It was thus necessary that gas burners be supplied in a variety of shapes and sizes so that they would conform to the shape of the walls of the large variety of different furnaces which were encountered in such installations.

The present invention has rendered it unnecessary to maintain such a stock of burner parts.

A burner indicated generally at In is provided for supplying fluid fuel to the combustion chamber I 2. The burner in the illustrated example comprises a tubular body member I4 within which the fluid fuel, such as gas, is mixed with proper quantities of air supplied by a fan (not shown) located within a fan casing l6 and adapted to be driven by a motor IS. The fuel is supplied through a line 20 for mixture within the tube l4, the operation of the burner mechanism being controlled by means located within the control box 22.

The fuel and air mixed in the proper proportions, is injected into the combustion chamber l2 where combustion is carried on. The combustion chamber comprises essentially a tray 24 which is composed of a channel-shaped metal part 26 which fits within and is telescopically received by an open-ended metal tray 28. The channel-shaped member 26 has secured to its forward end a relatively heavy metal plate 38 provided with an aperture 32 through which the nozzle and pilot of the burner l4 may project.

A plurality of complementary-shaped refractory blocks 34 of moulded material are provided adjacent the front end of the channel member 26 and fiush with the'rear of the plate 30. Such blocks are hollowed out in order to receive the nozzle and pilot box of the burner I8 and to provide a'passage therethrough for the fluid fuel being fed into the combustion chamber. The tray is telescoped to its proper position so as substantially to fill the ash pit of a furnace such as 36 and the bottom and sides of the tray are lined with bricks 38 and 48 of a similar refractory material.

The bottom lining bricks 38 are rabbeted along the sides and rear end of the tray as at 39 to receive the side and rear bricks 40.

Similar bricks 42 and 44 are provided over the top of the combustion chamber leaving an aperture 46 through which the hot products of combustion within the chamber may escape.

A baffle plate 48 is positioned over the aperture 46 and rests upon legs 50 and 52 depending from the bafile plate and located at the edge of the aperture. The forward leg 60 extends the full width of the baflie plate to prevent a flow of hot gases toward the furnace charging door 63. The rear leg 52 is of limited width so as not to interfere with the flow of hot gases toward the rear of the furnace.

After the bricks of refractory material have been fitted in place they are removed, coated with a refractory cement and reassembled in their proper position, the cement serving to bond the bricks together. This final assembly of the combustion chamber is accomplished within the ash pit of the furnace by reaching through the fire door 53 of the furnace and assembling the bricks in their proper position. In some cases it is necessary to cover the fioor of the ash pit with sand or ashes as at 54 in order to raise the combustion chamber to the proper height within the furnace, that is, to a plane in which the hot gases issuing from beneath the baiiie 48 will impinge upon the heat-transfer surfaces of the furnace. The emission port 60 may also be raised by turning the top bricks 42 on edge.

The spaces existing around the combustion chamber and the top bricks 42 of the chamber are filled as at 56 with a mixture of cinders and asbestos, although if asbestos is not available, cinders alone or gravel may be employed. This filling 56 is continued up to within a fraction of an inch below the top of the rim bricks 42 around the aperture in the top of the combustion chamher so as to form a level horizontal hearth extending in all directions from the combustion chamber to the side and front walls of the furmade or boiler 36. The remaining space below the top of the rim brick 42 is filled as at 58 with a refractory bonding cement to the level of the top of the rim brick 42.

Combustion is carried on within the chamber formed by the bottom and side bricks 38 and 48 and the rim brick 42 under a positive pressure generated by the burner I0, the burning vapors being required to move along the length of the combustion chamber during combustion and being subjected to the relatively high temperature of reflected heat within the chamber during such passage. The completely burned fuel is expelled at the top of the combustion chamber through the slot 68 formed between the underside of the pressure baflle 48, and the top of the rim bricks 42 by reason of the baffle being supported upon the legs 50 and 52. Combustion is carried on at such a rate and with so great an efficiency that the temperature of the gaseous products of combustion issuing from beneath the baffle reach a temperature of 2300" Fahrenheit. This extremely high temperature resulting from complete combustion is reflected by all the walls of the chamber and materially assists in the complete chemical combination of the incoming fresh and relatively cool fuel and air particles.

Reference to Fig. 9 will illustrate that the leg 58 extends entirely across the width of the bafile plate 48 in order to prevent contact of the flame being expelled through slot 60 with the front or fire door portion of the furnace or boiler 36. The supporting leg 52 is of small lateral dimension and does not interfere with the expulsion of the fiame or products of combustion through slot 60.

The relatively small dimension of the slot 60 with respect to the dimension of the intake aperture 32 is such as to cause the products of combustion issuing from the chamber to impinge with high velocity upon the walls of the furnace or boiler 36. After striking the furnace walls,

the products of combustion may travel upwardly along such walls, thereby yielding up all of theiravailable heat to the heat-transfer surface of the furnace. It will be noted, however, that the volume of the materials injected into the combustion chamber will be greatly increased by the increase in temperature from atmospheric to the neighborhood of 2300" Fahrenheit as well as by the expanding effect of combustion. Even if the slot were of greater cross sectional area than the intake aperture of the combustion chamber the linear speed of the burned gases issuing from the port 60 would be materially greater than the intake speed.

The pressure baflie 48 may be tilted to accommodate it to a relatively long rectangular furnace or a square furnace as shown in Fig. 7. This tilting is accomplished by either lengthening or shortening the leg 52.

It should be noted that the combustion chamber has a relatively large cross sectional area as compared with the burner nozzle. The relative areas of these parts will cause the fuel and air mixture injected by the burner into the combustion chamber to be retarded in its lineal velocity and will produce considerable turbulence and eddy currents in the mixture. On the other hand, the slot til beneath the baffle plate has a relatively small cross sectional area as compared with the area of the combustion chamber and which is at least no greater than the cross sectional area of the burner nozzle. The effect of such construction will be to cause the very hot products of combustion to issue from slot 60 at a relatively high speed, assuring that they will impinge directly upon the furnace heat-transfer walls.

It will thus be recognized that there has been provided a device which may be employed in central heating equipment of a multitude of sizes and shapes but which will not be subject to criticism on grounds of inefliciency. The fuel and air mixture is confined within the combus tion chamber under positive pressure until it is thoroughly burned, at which time the pressure baffle and the pressure within the chamber cause the extremely hot gases to be sprayed over the furnace walls, this process being continuousduring the heating cycle of the apparatus.

Although the invention has been described somewhat in detail, it will be appreciated that the foregoing description is not to be taken as limiting but only as illustrative of the manner at present best suited for practicing the invention. All equivalents falling within the scope of the attached claims are reserved.

I claim: 1. A combustion chamber comprising a pair of c hannel-shaped members, each having one material lining the interior of said tray upon the sides, ends, bottom and at least a portion of the top thereof to form a tunnel, an inlet, and an outlet from said tunnel for receiving materials to be burned and for discharging the products of combustion, respectively.

2. A combustion chamber comprising a pair of channel-shaped members each having one closed end and arranged one within the other to define an open-top telescoping tray, the end of one of said channel-shaped members being provided with a burner opening, refractory material lining the interior upon the sides, ends, and bottom of said tray and covering a portion of the open top thereof to form a tunnel having an inlet registering with said burner opening, and an outlet from said tunnel defined by the side and top refractory material surrounding the uncovered top portion.

3. A combustion chamber comprising a pair of channel-shaped members, each having one closed end and arranged one within the other to define an open-top telescoping tray, the end of one of said channel-shaped members being provided with a burner opening, refractory material lining the interior upon the sides, ends, and bottom of said tray and covering a portion of the open top thereof to form a tunnel provided with an inlet and an outlet from said tunnel defined by the side and top refractory material surrounding the uncovered top portion, and a bafile overlying said outlet.

4. A combustion chamber comprising a pair of channel-shaped members, each having one closed end and arranged one within the other to define an open-top telescoping tray, one of said channel-shaped members having a burner opening provided in the closed end thereof, refractory material lining the interior upon the sides, ends, and bottom of said tray and covering a portion of the open top thereof to form a tunnel provided with an inlet registering with the opening in said channel-shaped member, and an outlet from said tunnel defined by the side and top refractory material surrounding the uncovered top portion, and a baflie plate of refractory material covering said outlet and supported slightly above the top surface of the top covering refractory material.

5. A combustion chamber comprising a rectangular tunnel of refractory material having an inlet at one end, the other end being closed, the roof of said tunnel being provided with a rectangular outlet at the end of said tunnel away from said inlet and a rectangular baflle plate slightly larger than said outlet-supported upon legs from the roof of said tunnel and covering said outlet, said legs comprising a wide leg extending across and below one end of said plate and a narrow leg positioned centrally of and below the opposite end of the plate.

MORITZ L. MUELLER. 

